Radiant tube and convection oven

Abstract

An oven for heating a coating on a substrate, such as a painted vehicle body, including a first zone having radiant tubes and shields above the tubes and a second zone including side heat chambers having nozzles directing heated air onto a coated substrate and a hold zone. The radiant tubes may include a first linear portion extending through the oven and return loop beneath the substrate to conserve energy and sill ducts directing heated air against the underside of the vehicle body. The temperature is controlled by sensors contacting the radiant tubes and a proportional integral control system.

Description

RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application Ser. No. 60 / 513,748 filed Oct. 23, 2003.BACKGROUND OF THE INVENTION[0002]At present, paint and other coatings are baked or cured in a radiant oven, wherein the walls and / or floor are heated by combustion burners. In a typical automotive application, the painted vehicle body is conveyed through the radiant oven and the opposed side walls and generally the floor of the oven are heated by combustion burners which direct hot air into rectangular enclosures defining the side and bottom walls of the oven. This method of heating requires flame sensors to avoid a potential explosion which automatically turn off the flow of combustible gas to the burners in the event that the burner fails and combustible gas is directed into the enclosures thus shutting down the oven. The enclosures must then be purged of combustible gas before restarting the burners and restarting the oven. As a safety feature,...

AI Technical Summary

Benefits of technology

The patent describes a radiant tube and convection oven that combines the benefits of radiant heating and convection heating to heat a painted or coated substrate without overheating areas and conserving energy. The oven has three heat zones: a radiant bring-up zone, a convection bring-up zone, and a hold zone. The radiant tubes in the oven are positioned to maximize heating efficiency and the use of the hot gases from the radiant tubes to heat the fresh air prior to circulation through the oven. The three zones are collinear or axially aligned with the conveyor to allow the substrate to pass through all three sections or zones of the oven. The oven also includes a secondary heat recovery system to transfer heat from the hot gases. The radiant tubes extend through the oven and are directed towards the painted or coated substrate to improve heating efficiency. The hold zone has a lower volume of heated air and a constant temperature to further improve energy utilization.

Problems solved by technology

As will be understood by those skilled in this art, restarting a paint oven after shut down because of a failure of either the burner or a flame sensor requires time and thus considerable expense, but safety precautions must be maintained to avoid a hazardous condition.

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